week 1/2 DNA technology

State a couple of differences between genomic DNA libraries and cDNA libraries.

Genomic DNA libraries contain the entire genetic material of an organism, including both coding and non-coding regions such as introns and regulatory sequences, and are independent of the tissue type or developmental stage.

In contrast, cDNA libraries are made from mRNA, representing only the genes that are actively expressed in a specific tissue at a specific stage of development,

and they contain only coding sequences (exons), with no introns or regulatory regions.

Steps in making recombinant plasmids

1) Isolate the gene of interest (insert)

2)Cut the plasmid and insert with the same restriction enzyme

3) Mix the cut plasmid and insert

4) Join using DNA ligase

5) Introduce recombinant plasmid into bacteria (transformation)

What does a genomic DNA library contain? (vectors)

It contains all genetic material of an organism, including both coding and non-coding regions like introns and regulatory sequences.

Is a genomic DNA library tissue- or stage-specific? (vectors key features)

No, it represents DNA from the entire organism regardless of tissue type or developmental stage.

What does a cDNA library represent, and what sequences does it include? (vectore)

It represents only the genes expressed in a specific tissue at a particular developmental stage, containing only coding sequences (exons) without introns or regulatory regions.

Phases of the Transcription Cycle

Initiation: RNA polymerase binds the promoter and unwinds the DNA

Elongation: RNA polymerase moves along the gene, synthesising RNA

Termination: RNA polymerase stops and releases the RNA product

What is transcription, and which DNA strand is used as the template?

Transcription is the process of making an RNA copy of a gene. The antisense (template) DNA strand is used to produce a complementary sense RNA strand.

What happens during the initiation and elongation stages of transcription?

During initiation, RNA polymerase binds to the promoter and unwinds the DNA. During elongation, RNA polymerase moves along the antisense strand, adding RNA nucleotides to build the RNA strand.

What occurs during termination in transcription?

RNA polymerase reaches a termination signal, stops transcription, and releases the newly made RNA molecule.

what is a Promoter

A specific DNA sequence near the start of a gene where RNA polymerase binds to begin transcription.

What is the role of RNA polymerase?

Catalyses the formation of phosphodiester bonds between ribonucleotides.